Patent EA-000653-B1 (EA)
Title: Rotary cutoff device and method
IPC: B23D25/02
Filed: 1997-05-09
Abstract: 1. Apparatus for cutting a moving sheet of web material, into predetermined lengths, and comprising; a pair of lower and upper cutoff rolls the rolls defining a gap therebetween for movement of the sheet web material therethrough, wherein one of the rollers has a moving cutoff blade for cutting a sheet of web material, and a means for operating said lower and upper rolls in unison whereby to rotate the same in unison, wherein a stop bar on one of said lower and upper rolls, defining a cutoff location and, a moveable cutoff blade on the other of said lower and upper rolls, and and, a plurality of plunger members extending through said other of said roll cam means on said plungers members, and cam operating means located outside said roll in registration with said cam means, and including the step of causing rotation of said roll whereby said cam means engages said cam operating means and cause said plungers to advance said cutoff blade towards said stop bar for moving said cutoff blade towards and away from said stop bar, said cutoff blade being offset slightly with respect to said bar whereby said cutoff blade moves adjacent said bar and achieves a shearing action cutting said web material, movable mounting means for moving said cam operating means, and a slide bar moveable relative to said mounting bar whereby to raise or lower said mounting bar, and power operated means for moving said slide between two positions. 2. A cutoff apparatus as claimed in Claim 1 and including means for starting and stopping the cut off rolls by means of power operated means connected to a length measurement device located upstream of the cutoff apparatus, for measuring the length of the web material and for sending signals to the power operated means. 3. A cutoff apparatus as claimed in Claim 1 wherein the cutoff blade is mounted at a slight shear angle relative to the stop bar, so as to provide a cutting action, which starts at one side of the web and continues to the other side. 4. A cutoff apparatus as claimed in Claim 1 wherein said two rolls are preferably of relatively small diameter, so that they may be started and stopped easily, and so the position of each cut may be precisely regulated. 5. A cutoff apparatus as claimed in Claim 1 wherein, as soon as the cut is completed, the cutting blade is retracted once more, so that the upstream end of the web can continue passing between the rolls without obstruction. 6. A cutoff apparatus as claimed in Claim 1 wherein said rolls are of generally oval shape in section, and define two apexes, and said stop bar being located at one apex of one said roll, and said slot and blade being located at an apex of the other said roll. 7. A cutoff apparatus as claimed in Claim 2 including through openings extending diametrically through said blade roll and said plungers being located in said through bores and means biassing said plungers into a position in which they are retracted within said roll. 8. A cutoff apparatus as claimed in Claim 7 and wherein said stop bar roll defines a right angular wherein said stop bar roll defines a right angular shoulder at one apex, and fastening means securing said stop bar to said shoulder, whereby said stop bar is removable for servicing. 9. A method of cutting a moving sheet of web material, for cutting the same into predetermined lengths by passing said sheet web material through a pair of lower and upper cutoff rolls the rolls defining a gap therebetween for movement of the sheet web material therethrough; in which said moving cutoff blade is connected to a plurality of plunger members extending through said other of said rolls, cam means on said plungers members, and cam operating means located outside said roll in registration with said cam means in which said moving cutoff blade is connected to a plurality of plunger members extending through said other of said rolls, cam means on said plungers members, and cam operating means located on said mounting means and a slide bar moveable relative to said mounting bar whereby to raise or lower said mounting bar, and power operated means for moving said slide between two positions, characterized in that comprising the steps of: discontinuous operating said lower and upper rolls (12,14) whereby to rotate the same in unison, there being a stop bar (32) on one of said lower and upper rolls, defining a cutoff location and, a moveable cutoff blade (52) on the other of said lower and upper rolls; and, moving said cutoff blade (52) towards and away from said stop bar (32), said cutoff blade being offset slightly with respect to said bar whereby said cutoff blade moves adjacent said bar and achieves a shearing action cutting said web material cutting said sheet web material, including the steps of starting and stopping the cutoff rolls by means of power operated means connected to a length measurement device located upstream of the cutoff apparatus, for measuring the length of the web material and for sending signals to the power operated means.